Railway-traffic-control apparatus.



R. M. GILSON.

HAiLWAY TRAFFIC CONTROL APPARATUS.

APPLICATION FILED AUG. I I, 1916.

Patented Apr. 2, 1918.

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WITNESSES rTnn STATES PATENT onrion ROBERT M. GILSON, F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENN SYLVANIA.

Specification of Letters Patent.

Patented Apr. 2, 1918.

Application filed August 11, 1916. Serial No. 114,375.

To all whom it may concern:

Be it known that I, ROBERT M. GILSON, a

citizen of the United States, residing at following is a specification.

My invention relates to indication apparatus for railway traffic controlling devices. I shall describe one form of apparatus and circuits embodying my invention and then point out the novel features thereof in claim.

The accompanying drawing is a diagrammatic view showing two railway switches and indication devices therefor, and one form of apparatus and circuits embodying my invention for the control of each of said indication devices by said switches.

Referring to the drawing, reference characters A and A designate railway switches which are controlled by levers C and C respectively, of an interlocking machine. The manner in which this control is accomplished is fully described in Patent No. 1,101,039 issued to Gr. R. Scattergood and H. A. Wallace on June 23, 1914. Briefly, switch A is operated by a motion plate F which is adapted to be reciprocated by a motor M comprising solenoids 10 and 11 operating a plunger 12 secured to the motion plate. The circuits (shown dotted) for the solenoids 10 and 11 are controlled by the lever C by means of a contact finger 18 which engages contact point 4.4 or 45 according as lever C is in the normal or reverse position respectively, so that movement of lever C from normal to reverse causes movement of switch A from the normal position (shown on the drawing) to the reversed position and the return movement of the lever to the normal position causes operation of the switch to the normal position. The posltions of switch A are controlled by lever G in similar manner.

The movements of. lovers G and C are controlled by indication apparatus as fully described in the aforementioned patent. For lever C this apparatus comprises segments K and K coacting as well understood in the art, with latches 29 controlled by magnets R and N in such 'manner that a comletereversal oflever C can be effected only a magnet it is energized whenthe'lever are rives in the middle of its stroke, and a complete movement of the lever in the opposite direction is ossible only after a similar energization o magnet N. The magnets N and R are controlled as described in the said patent, by contact fingers 25 and 26 operated by lever C, and by a relay D responsive to reversals of current, this control being such that the magnet N can be energized only when the relay D is energized normally, closing contact 1%, and the magnet R can be energized only when the relay D is energized reversely, closing contact 15, whereas neither magnet can be energized when relay D is decnergized. Magnets R and N of lever C are controlled by a relay D in similar manner.

Relay D as here shown comprises two windings f and a. Winding f is highly inductive and draws a lagging current from generator 19 through conductors 20 and 21. Winding a is supplied with current from a circuit comprising a transformer T encrgized from alternator 19 by conductors 22; a condenser K, a pole-changer P operated by motion plate F, line conductors 23 and 2 1,

extending from pole changer P to the terminals of the relay D, an inductive impedance 2' connected in series with winding a preferably within the relay casing, which casing is indicated by the dotted outline r. The combined inductance of impedance 2 and winding a is substantially equal to the reactance of condenser K so that the circuit is substantially resonant. The current flowing in the circuit is limited only by the effective resistance thereof, which is quite small in comparison with the reactance of either the condenser K or the inductance of the impedance coil 2' and winding a. A comparatively large current flows therefore through winding a, which current, being displaced almost ninety degrees from the lag ging current in winding 7, coacts with the current in the latter winding to cause operation of the relay contacts. The direction in which these contacts are operated is governed by the direction of current in winding (2 relative to the direction of the current in winding 7. The direction of the current in winding a is controlled by "pole-changer P, this control being such that relay D closes contact 14 when the switch A is in its norunderstood in the art.

switch is in the-reversed position. During the movement of the switch from one position to the other the contact finge s 16 and 17' of pole-changer P are short-circuited by a wire 51 so that no current can reach winding a and both contacts 14 and 15 are open. The relay D is Controlled in the same manner by switch A.

A brief description of the operation of switch A by lever C is as follows:

When lever C is turned clockwise toward its reversed position, the lever is arrested after it has been moved through half of its stroke by a dog 28 on segment K engaging latch in this position of the, lever, fill". 'ger 18 engages contact 45, thus, closing the circuit for solenoid 11 of motor M, sothat plunger 12 shifts motion plate F to the right causing reversal of switch A. During this movement of the switch relay D is deenergized, as hereinbei'ore explained, so that the circuits or" both indication magnets R and N are opened and lever C is locked in its halt stroke position. W hen, however, the switch arrives in its reversed position, relay D is energizeo reversely, closing at contact 15 the circuit for magnet R, thus unlocking the lever to permit its movement to the reversed position. The operation of the switch in the opposite direction is effected in a similar manner by the return movement or the lever to normal.

V The apparatus for the control of switch A is operated in similar manner by lever C.

. Signals governing trafiic over the switches are controlled by levers C and G, as well It is therefore important that each lever always is in position corresponding to the position of the switch which it governs, which is secured as described above, by arresting the lever the halt-stroke position until a full m, ment oi the switch has been efiectedf As was pointed out hereinbefore, the locking of the lovers C and C in their center positions is secured by the deener 'ization of relays D. and D respectively. rdinarily the deenergization or" the relays is assured only by short-circuiting the conductors 23 and at the pole-changer. But it may happen, due to a variety of circumstances, that this short circuit is rendered partially or wholly ineffective, as, for instance, in case of a break 60 in wire 23 of the circuit for winding a or. relay D. It now the conductors 25 3 and 2eof relays D-and are crossed, as; indicated by dotted connections 62, relay D "receives current fro nitranslormerf T, while our cut would 6 rate uneasy conct s ca iiselrelease cit-lever. (l iridlipflfidi 4 switch A iif the asst ted the a verhe are a in w Washington,

1am ls hrtea proper phase displacement from the current in the other relay winding 7. The lastmentioned conditions are prevented by my invention, as l shall now explain. I

The circuit now fed from transformer T comprises at one end condenser K and at the otherend thcwindings a and impedances z of the two relays D and D connected in parallel. The circuit has, in comparison with the normal resonant circuits for windings a of relay D and D, the same condensive reactan ce but only half the inductive reactance. Only an approximate halfof the condensive reactance of the circuit, therefore, is counterbalanced by the inductance of the circuit, so that the circuit is no longer resonant and permits but a small leading current to flow from transformer T, half of this current iiowing through the windings a of each relay. This current would be unable to operate the re. lay contacts even under the best phase relation to the currents in the other winding f. Actually, however, the current in winding (4 of each relay has considerable lead and the current in winding f has considerable lag, so that the currents are displaced in phase nearly 180 degrees. lhus both relays D' and D are effectively prevented from operating their contacts, making it impossible to effect an operation of either lever C or C" until the circuits are restored to their normal conditions.

Although I have herein shown only one "form of apparatus andcircuits embodying my invention, it understood that various changes and modifications may be made within the scope oi the appended claim without departing from'the spirit and scope of my invention.

Having thus described my invention, what I claim is:

In combination, two railway tralfic controlling devices, indication apparatus for each device including an induction motor having two, windings, a source of alternating current, twocircuits supplied with current from said source and controlled by said two devices respectively and including respectively'one winding of each'inotor, each of said. circuits including an inductance ad jacent one end and a condenser adjacent the other and each circuit being tuned to resonance at the frequency of said source, and means for supplying the other winding of each motor with current from said source. In testimony whereof I aliix my signature in presence of two witnesses.

non-Ear M. GILSIONQ It). it. 

